Acquired dyslexia, impaired ability to read caused by brain damage in a previously literate person, takes a variety of forms. This fact is now frequently interpreted by arguing that the information processing system we use when we read is complex, with various subcomponents. The kinds of theoretical interpretations we have been discussing have obvious implications for the treatment of acquired dyslexia. There would seem little point in treating surface dyslexia by training the patient in phonics, that is, in the use of letter-sound rules, when this aspect of reading remains well preserved or even intact and when the use of a rule-based reading procedure is in fact what is causing the patient's paralexias. Surface dyslexia is one of the syndromes of acquired dyslexia, and the regularization error is one of its symptoms. However, like other syndromes, surface dyslexia is not uniform across patients: It can arise in different ways in different patients.